AEDs Survive the Test of Time

With a more sophisticated understanding of sudden cardiac arrest (SCA) and improved technology, the field of resuscitative medicine is moving forward at a rapid clip. The missing piece to the puzzle, however, is getting more automated external defibrillators (AEDs) into more public spaces, coupled with education and training.

AED outreach

Hospital CEOs understand the value of having AEDs throughout their buildings and offices. But they may underestimate the importance of reaching out into the community regarding the placement of AEDs, along with educational and training programs for their proper use.

“If you view a hospital as a community resource, the hospital system should be involved in the whole spectrum of care,” says Vincent N. Mosesso Jr., MD, medical director of the University of Pittsburgh Medical Center’s prehospital care and medical director of the Sudden Cardiac Arrest Association. “We know the way to improve survival from cardiac arrest is early care. The only way to impact that is to ensure the chain of survival is improved.”

Not-for-profit hospitals, in particular, could get more involved in outreach AED programs as part of their overall mission. In 2008, Sen. Charles Grassley, R-Iowa, while investigating some complaints against not-for-profit hospitals, said that nonprofits are “losing sight of the public service that comes with tax-exempt status.” For a few years now, some states have required standardized reporting of community benefits. This year, however, the IRS has mandated that not-for-profit hospitals standardize the reporting of community benefits.

“The overall health mission of a hospital is to decrease disease burden,” says Ranjit Suri, MD, director or electrophysiology at Lenox Hill Hospital in New York City. “If you become involved with the community, you can gain recognition, respect and trust. But the main reason to start a community AED program is because sudden cardiac arrest is a huge problem.”

As a new initiative, Suri and colleagues have placed 20 AEDs in various public venues around Lenox Hill, including places of worship and senior centers. Part of the educational leg of the program is to tell people that calling 9-1-1 is not enough. “Time is brain,” Suri says. “If more than seven minutes elapse from the time of arrest until a responder is on the scene, there is a good chance the victim won’t survive, at least neurologically intact.” Partners in the AED outreach program with Lenox Hill are Cardiac Science and Physio-Control.

Simple to apply

Having AEDs available to people without medical backgrounds is a great concept, but does it work? In a word, yes, says David Cooke, MD, vice president of quality and safety at Central DuPage Hospital in Winfield, Ill. He cites several seminal studies of the use of AEDs by nonmedical personnel that have demonstrated their effectiveness when used quickly and properly. Venezuela et al found that trained casino security guards could effectively use AEDs (N Engl J Med 2000;343:1210-1216), while Page et al found that airline attendants trained in the use of AEDs also helped save lives (N Engl J Med 2000;343:1206-1209). Caffrey et al found that untrained bystanders in two Chicago airports effectively deployed AEDs to help people suffering from SCA.

Unfortunately, the benefit of AEDs placed in homes has not been proven. Bardy et al found no significant difference in death rates between control homes, which used CPR, and those equipped with an AED (N Engl J Med 2008;358:1793-1804).

Participants had had a previous MI and were not candidates for an implantable cardioverter-defibrillator (ICD).

Much of the AED technology in place today has been in use for a decade. The devices have been able to discern normal from abnormal rhythms and they’ve had the capability to record the resuscitation process for later analysis and training. One of the newer advances is the ability of the devices to guide bystanders through the rescue process and provide feedback in terms of the length and depth of chest compressions.

If a bystander, for example, has difficulty attaching the patches, the AED prompts the user to attach them until they are secured. It will not skip ahead to the next step. After the initial shock and several minutes of CPR, if the victim is still in abnormal rhythm, the AED will recommend another single shock. If the rhythm is normal, the device will recommend the user check for a pulse and continue CPR if necessary.

Wearable AEDs Act as Bridge for Some at Risk for Sudden Cardiac Arrest
New guidelines for implantable cardioverter-defibrillators (ICDs) recommend a waiting period of 40 days post-MI and up to 90 days post-revascularization or the diagnosis of nonischemic cardiomyopathy. These patient populations are at risk of sudden cardiac arrest (SCA), but some will heal on their own, while others will need an ICD. Some cardiologists handle this “cooling off” period through a wearable defibrillator (LifeVest, Zoll Medical, currently the only such product approved by the FDA).

At AHA.07, Ranjit Suri, MD, director or electrophysiology at Lenox Hill Hospital in New York City, and colleagues presented data from 25 patients showing that the LifeVest saved 25 percent of patients from receiving an unnecessary ICD. Three of the patients who received an ICD ultimately had ejection fractions greater than 35 percent, suggesting a longer period of assessment may be necessary. Two patients died while not wearing the vest, emphasizing the importance of compliance, Suri says.

In 2005, CMS had approved reimbursement for the use of the LifeVest in the aforementioned patient populations.

Randy Lieberman, MD, director of cardiac electrophysiology at Harper University Hospital in Detroit, and colleagues recently submitted a paper detailing their experience with 300 patients wearing the vest.

“The data are positive,” Lieberman says. “We show who are the appropriate patients, the appropriateness of the therapy and how to pursue this interim therapy that promises to improve outcomes and save healthcare dollars.”

Changing with the times

In 2005, a change to the resuscitation guidelines stated that it was more beneficial to apply one shock via the AED and then to immediately begin CPR (Circulation 2005;112[Suppl I]:IV-1-IV-203). Previously, rescuers would shock the victim, wait to see if the rhythm was converted and if not, repeat the process two more times. The time lapse between the initial and last shock is critical for the patient, says Mosesso. “We now have a better appreciation for beginning CPR as soon as possible,” he says.

Manufacturers responded to the change in guidelines by reprogramming AEDs so they cannot give more than one shock successively. “That is an important advance,” says Richard L. Page, MD, president of the Heart Rhythm Society and chair of the department of medicine at the University of Wisconsin School of Medicine and Public Health, Madison, Wis. “Most initial shocks successfully convert the rhythm. But even if they don’t, we believe it’s better to resume CPR immediately, without even checking for a pulse.”

The updated guidelines also recommend uninterrupted CPR, meaning that rescuers should not stop to force their breath down the victim’s airway. “Hands only,” says Page, who coauthored the guidelines. “The most important aspect is to reperfuse the heart muscle. Continuous CPR is the best option for that.”

Performing uninterrupted CPR also is easier for bystanders. Along with today’s sophisticated AEDs, hospitals have more reasons than ever to help distribute AEDs to their surrounding communities.

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